Exposure to smoke

Firefighters being exposed to toxic substances in smoke is a realistic hazard. Some of these toxic substances pose a health risk and can lead to occupational disorders. Therefore it is very important to know which toxic substances firefighters are exposed to and how these substances can be absorbed by the human body and form a potential health risk. In a previously performed literature study, it has been established that there is no causal relationship between exposure to toxic substances in smoke and cancer, despite the fact that in a number of studies it has been shown that among firefighters some cancers occur more often than in the rest of the population. In this research project, the central question was what should be done to minimize the exposure to toxic substances before, during and after the firefighting of firefighters, so that the chance of any (later) health damage is limited as much as possible?

In order to gain more clarity, a number of aspects relating to exposure to toxic substances in smoke were investigated in several (sub-)studies. A model and literature study has determined which toxic substances are most commonly found on the fire-ground and how these substances can be absorbed by the body. The permeability of the skin for toxic substances, as one of the possible absorption routes in the body, has been experimentally investigated to determine if the protective barrier function changes as a result of wearing protective clothing. In another (sub-)study, the degree of contamination with toxic substances of turn-out gear is analysed and the residual contamination remaining after cleaning is investigated. Finally different circulating guidelines of the Safety Regions on proper working in the fire services have been investigated on differences and similarities.

The results of the model and literature study have shown that inhalation is the most important absorption route for many of the 32 most common toxic substances in smoke. However the skin is a probable route for two substances, namely hydrocyanic acid and the polycyclic aromatic hydrocarbon benzo(a)pyrene. This latter substance is carcinogenic. The (sub)study to the skin characteristics has shown that the barrier function of the skin is reduced e.g. the increased moisture of the skin under the influence of wearing protective turnout clothing, It has not been investigated if the decreased barrier function of the skin is of influence on the absorption of benzo(a)pyrene. However previous research has also not shown that people with a severely reduced skin barrier develop more cancer by the absorption of benzo(a)pyrene.

The (sub-)study to the contamination with toxic substances from the 3-layer turnout gear has shown that most of the pollution does not pass the middle layer of the turnout gear. The substances that are toxic to skin can hardly be found on the inner layer and therefore are not of any danger. Although there are no clear exposure standards for harmful polycyclic aromatic hydrocarbons, standards have been set in the European Union for skin contact with these substances in new clothing. These standards have sometimes been exceeded for the middle layer of the tested turnout gear, but that result was mainly attributable to one strongly contaminated turnout suit of a training-centre.

After cleaning the turnout gear, the contamination has spread partly over the simultaneously washed suits. It has been found that, with a larger number of suits per wash, more contamination remains in the turnout gear. In order to prevent the relatively clean inner layer of the turnout gear from being contaminated during the cleaning process, it is possibly an idea to clean the dirty outer layers separately from the inner layer in future. Based on the current results, further research to the complete cleaning process of turnout gear is desirable.

Based on the results of the (sub-)studies and the various occupational hygiene guidelines applied by the Safety Regions in firefighting activities, it can be concluded that there is a great awareness within the Netherlands Fire Services regarding the hazards of exposure to smoke. Firefighters must be familiar with the hazards of exposure to toxic substances in smoke beforehand and take the necessary precautionary measures to prevent exposure to toxic substances in smoke as much as possible. They must protect themselves with all possible measures during the firefighting activities to prevent absorption of toxic substances in smoke by the inhalation route or the skin. Afterwards they must isolate the contaminated (protective) means as soon as possible and ensure that the resources are cleaned as adequately as possible to minimize the chance of being exposed to toxic substances on and in the (protective equipment). Personnel of laundries who are in charge of cleaning the equipment must finally prevent themselves from coming into contact with the toxic substances in the (protective) equipment by use of suitable protective means.